NZR G class (1928)
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| NZR G class (1928) | |
| Power type | Steam |
|---|---|
| Builder | Beyer-Peacock, NZGR |
| Build date | 1928 |
| Configuration | Garrat: 4-6-2+2-6-4 Pacific: 4-6-2 |
| Length | 69' 8" |
| Width | 8' 6" |
| Height | 11' 6" |
| Total weight | 136 tons |
| Career | NZGR |
| Number in class | Garrat: 3 Pacific: 6 |
| Number | Garrat: 98 - 100 Pacific: 95 - 100 |
| First run | Garrat: 1928 Pacific: 1937 |
| Last run | 1956 |
| Preserved | 0 |
| Disposition | Withdrawn |
The NZR G class was a type of Garratt steam locomotive used in New Zealand, the only such Garratt type steam locomotives ever used by New Zealand Government Railways. They were ordered to deal with traffic growth over the heavy gradients of the North Island Main Trunk and to do away with the use of banking engines on steep grades. They were one of the few Garratt designs to employ six cylinders. A mechanical stoker was used to feed coal into the locomotive.
Numerous design faults occurred and the locomotive's fate was sealed when the K class was introduced in 1932. The locomotives were much too powerful for the drawgear then in general use on ordinary rolling stock and relatively short crossing sidings made it impractical to haul loads commensurate with the power of the locomotive.
[edit] Rebuilds
In 1937 the three ill-fated Garratts were dismantled and certain portions incorporated into six G class three-cylinder Pacific locomotives. The engines were provided with an AB class boiler, a new roller bearing trailing truck was fitted, also a new cab, and the Vanderbuilt tender of similar design to that of the AB class although larger and of all-welded construction. All bogies on the engine and tender were equipped with roller bearings, and other modern equipment included power reversing gear and exhaust-steam injectors. The three cylinders retained their conjugated valve gear from the Garratts, but this gear was rather light in construction and gave persistent trouble in maintaining the correct settings. The locomotives were used in the South Island mainly on the Christchurch to Arthur's Pass section of the Midland Line and mainly in freight service. The class was far from popular and their shortcomings far too numerous to justify the high cost of major improvements.
